Staff will be keeping a careful count of how many customers are tucking into the popular chicken soul sandwich, with the 20,000th person to do so winning themselves a free sandwich every week for a year.

May Street Larder co-owner Eamon Sullivan said with more than 19,200 sold already, the sandwich, packed with buttermilk fried chicken, avocado, smoked sour cream, jalapenos and chilli maple syrup on a polenta and cheese waffle, was one of the most popular items on the menu.

“We wanted to create a fun Willy Wonka style competition and give the ‘golden ticket’ to the lucky winner, which entitles them to one free soul sandwich a week for a year,” he said.

“I don’t think our really health-conscious customers will be lining up to win the competition, but perhaps our social butterfly customers who come in with their sunglasses on after a big night, to line their stomachs with a Soul Sandwich might be interested.

“It is the unofficial best hangover cure in Perth, I think.

“Free food always tastes better after all, and especially knowing you can come back the week after and have your favourite dish again.”